Application of the NICO Myriad

Neurosurg Focus 30 (4):E6, 2011

Emerging technology in intracranial neuroendoscopy: application of the NICO Myriad

Technical note

Brian J. Dlouhy, M.D., Nader S. Dahdaleh, M.D., and Jeremy D. W. Greenlee, M.D. Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa

Improvement in fiber optics and imaging paved the way for tremendous advancements in neuroendoscopy. These advancements have led to increasingly widespread use of the endoscope in neurosurgical procedures, which in turn incited a technological revolution leading to new approaches, instruments, techniques, and a diverse arma- mentarium for the treatment of a variety of neurosurgical disorders. Soft-tissue removal is often a rate-limiting aspect to endoscopic procedures, especially when the soft tissue is dense or fibrous. The authors review a series of cases involving patients treated between August 2009 and October 2010 with a new device (the NICO Myriad), a non–heat- generating, oscillating, cutting, and tissue removal instrument that can be used through the working channel of the endoscope as well as in open neurosurgical procedures. They used this device in 14 purely endoscopic intracranial procedures and 1 endoscope-assisted keyhole craniotomy. They report that the device was easy to use and found that tissue resection was more efficient than with other available endoscopic instruments, especially in the resection of fibrotic tissue. There were no observed device-related complications. The authors discuss the technical aspects of using this device in endoscopic resection of pituitary tumors, craniopharyngiomas, and colloid cysts. They also demonstrate its use in hydrocephalus and intraventricular clot removal and discuss its potential use in other neurosurgical disorders. (DOI: 10.3171/2011.2.FOCUS10312)

Key Words • hydrocephalus • pituitary tumor • colloid cyst • craniopharyngioma • intraventricular clot • surgical technique

ince the beginning of modern medicine, neurosur- debulking of masses larger than a few centimeters in di- geons have tried to find more efficacious and ef- ameter due to a lack of endoscopic instrumentation. This ficient ways to surgically treat intracranial tumors, may lead to abandoning the consideration of an endo- hydrocephalus,S seizures, and many other neurological scopic approach in favor of a more traditional open pro- disorders. Utilizing an endoscope for visual assessment cedure. There is a need for technology that works in con- of the ventricular system as well as other parts of the junction with the endoscope for more efficient removal brain is a very old concept. With a unique combination of soft tissue and lesions that otherwise would be more of technological advancements in lens development,2 difficult to remove with simple suction and current endo- charge-coupled devices, and fiber optics, this old concept scopic tumor forceps and dissectors. became a widespread reality in the last 2 decades.31 The The NICO Myriad (NICO Corp.) is a recently de- endoscope is now an essential tool of the neurosurgeon veloped device that is used in multiple intracranial en- and is used alone or in an accessory fashion during mi- doscopic procedures for soft-tissue resection. We report crosurgery for the treatment of many different types of on a series of cases in which we utilized this tool in the intracranial and spinal pathology. resection of pituitary adenomas, craniopharyngiomas, As with all technology, there are limitations in neu- and colloid cysts. We also demonstrate its use in hydro- roendoscopy that need to be overcome. Depending on cephalus and intraventricular clot removal, and discuss its the size of a lesion, a purely endoscopic approach for potential use in other neurosurgical disorders. We discuss resection may be technically difficult or require signifi- the advantages and disadvantages of using this device in cant operative time, given the difficulties with efficient these illustrated cases.

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Patient Population and Surgical Device lifting his foot off the foot pedal (Fig. 1A). This allows the surgeon to observe precisely the tissue that is to be Patient Population cut and resected and avoid cutting structures drawn into Between August 2009 and October 2010, 14 patients the aperture inadvertently. The aperture can be rotated underwent purely endoscopic intracranial procedures and via a control knob on the handpiece, and the shaft can be 1 patient underwent an endoscope-assisted open keyhole gently bent if needed (Fig. 1C). All removed tissue can be craniotomy at the University of Iowa Hospitals and Clinics captured in the collection chamber (Fig. 1B), which al- in which the NICO Myriad was used for various reasons lows for pathological analysis with limited crush artifact (Table 1). Of these 15 patients, 5 patients had pituitary ad- from the device. enomas, 3 had colloid cysts, 3 had craniopharyngiomas, 2 Unlike ultrasonic devices3 or laser devices,19 the had loculated hydrocephalus, 1 had a pineoblastoma, and Myriad is purely mechanical and generates no heat at the 1 had a tuberculum sellae meningioma. resection site or along its shaft (Fig. 1C and E). It may also be used for spinal tissue or tumor resection in minimally Surgical System invasive and open surgical approaches. It is a multifunc- The NICO Myriad is a minimally invasive surgical tional instrument that combines the capabilities of scis- system specifically designed for the removal of intracra- sors, suction, and a blunt dissector (Fig. 1E). The device’s nial and skull-base soft tissues with direct, microscopic, low-profile design provides improved access to hard-to- or endoscopic visualization (Fig. 1A–E). The technology reach tumor sites and better visibility to the surgical field, platform is based on combining a high-speed reciprocat- especially during tumor resection through narrow corri- ing inner cannula within a stationary outer cannula and dors (Fig. 1B–E). The system is available in a variety of electronically controlled variable suction. The instrument diameters, lengths, and configurations to meet the diverse relies on a side-mouth cutting and aspiration aperture lo- needs of patients and clinical presentations in intracra- cated 0.6 mm from the blunt dissector end (Fig. 1E). The nial, skull base, and endoscopic procedures. The reusable functions of the device are operated via a foot pedal that main console, stand, and foot pedal (Fig. 1A and B) cost allows for precise control of the variable-strength suction approximately $94,000 (US) and the single-use dispos- and activation or deactivation of the cutting blade (Fig. able handpieces (Fig. 1C) cost around $2900. 1A). The combination of gentle forward pressure of the aperture into the tissue to be removed and suction draws Results and Illustrative Cases the desired tissue into the side aperture, allowing for controlled and precise tissue resection through the recip- In all cases, the device was easy to use and we found rocating cutting action of the inner cannula. In addition tissue resection to be safe and efficient. There were no ob- to the suction strength being controlled by the graded served device-related complications. amount of depression of the foot pedal, the strength can Tumor Resection be governed via a knob on the console (Fig. 1A and B). Importantly, the surgeon can immediately stop suction by Neuroendoscopic techniques and approaches are of-

TABLE 1: Summary of clinical and demographic characteristics in patients treated using the Myriad system*

Case No. Age (yrs), Sex Diagnosis Approach Reason for Use 1 46, M fibrous pituitary adenoma transsphenoidal tumor resection 2 31, F colloid cyst transcortical tumor resection, septostomy, intraventricular clot removal 3 74, F fibrous pituitary adenoma transsphenoidal tumor resection 4 7, M loculated hydrocephalus transcortical cyst fenestration 5 49, F craniopharyngioma transsphenoidal tumor resection 6 31, F colloid cyst transcortical tumor resection 7 27, M prolactinoma transsphenoidal tumor resection 8 52, F craniopharyngioma transsphenoidal tumor resection 9 67, F craniopharyngioma transsphenoidal tumor resection 10 32, F loculated hydrocephalus transcortical cyst fenestration 11 47, F tuberculum sella meningioma subfrontal craniotomy tumor resection 12 26, F colloid cyst transcortical tumor resection 13 58, M prolactinoma transsphenoidal tumor resection 14 25, F pineoblastoma transcortical tumor resection 15 77, F pituitary adenoma transsphenoidal tumor resection

* There were no device-related complications.

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Fig. 1. The Myriad system. A: The entire system, with console, collection chamber, and foot pedal on movable stand. B: Close-up view of the console, handpiece, and collection chamber. C: Close-up view of the handpiece resection instrument. D: The NICO Myriad 1525 intraventricular resection device inserted into an Aesculap MINOP WC endoscope. E: Close-up view of the end of the resection device in the endoscope from panel D; arrow points to the side-mouth cutting and aspiration aperture, which is located 0.6 mm from the blunt dissector end to protect neurovascular and other critical structures. Bar = 1 cm. ten considered too difficult for treatment of large intra- tion (Fig. 2C–G). After centrally debulking the tumor, we cranial tumors due to prolonged operative time and lack were able to quickly shave the tumor off the diaphragma of instrumentation for efficient cytoreduction with ac- sellae (Fig. 2C–E) without tearing the diaphragma (Fig. ceptable preservation of normal surrounding structures. 2F and G). In endonasal approaches such as this, the This limitation spurred the creation of the NICO Myriad, Myriad can be used directly, adjacent to a standard 4-mm which is designed for working within the limited space endoscope, and without a working channel. It is also com- provided by the endoscope for efficiently removing intra- patible with microsurgical endonasal approaches. Gentle cranial tumors without generating heat or damaging adja- bending of the tip can provide additional working angles cent eloquent brain tissue. and trajectories when used with angled endoscopic views. Rotation of the tip via the handpiece dial facilitates direc- Pituitary Adenoma. In the last 2 decades, the endo- 22 tion of the cutting aperture away from critical structures scopic endonasal transsphenoidal approach has become such as the cavernous sinus or internal carotid arteries. a very common procedure for resection of parasellar Our patient experienced no complications and did well masses.1 To make this approach more feasible, microneu- 4,21 postoperatively; near-total resection of the macroadeno- rosurgical instruments were modified. However, tech- ma was achieved, despite the fibrous nature of the tumor nological limitations still persist. Pituitary macroadeno- (Fig. 2B). mas are usually soft and friable but have been reported to be fibrous and tough in 5%–13.5% of cases.17 Fibrous Craniopharyngioma. Craniopharygiomas are chal- macroadenomas can be difficult to remove with simple lenging to resect through an open12,13 or transsphenoi- suction and ring curettes.35 We demonstrate an illustrative dal approach.7,9,20,29 Many surgeons have demonstrated case in which the Myriad helped remove a fibrous pitu- successful resection of craniopharyngiomas through itary macroadenoma (Case 7 in Table 1). This 27-year-old an extended endoscopic endonasal transsphenoidal ap- man with a history of headaches was found on MR imag- proach.7,14,20 Nevertheless, endoscopic resection of thick- ing to have a large sellar prolactinoma (Fig. 2A), which ened cyst walls and nonfriable tumor tissue can be diffi- became unresponsive to medical therapy and required cult. We present an illustrative case (Case 5) of a 49-year- surgical intervention. The patient underwent endoscopic old woman who presented with headaches and hormonal endonasal transsphenoidal resection of the mass. He had imbalance, with MR imaging demonstrating an enlarging been previously treated with cabergoline, and the pitu- sellar and suprasellar cystic and solid mass with exten- itary tumor was quite fibrous28 (Fig. 2C–G). Using stan- sion into the interpeduncular cistern and mass effect on dard suction and ring curettes proved to be difficult and the midbrain (Fig. 3A). She underwent an extended en- time consuming; therefore the Myriad was used for resec- doscopic endonasal transsphenoidal resection of the tu-

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Fig. 2. Case 7. Fibrous pituitary macroadenoma. A: Preoperative sagittal contrast-enhanced T1-weighted MR image demonstrating a large mass expanding the sella. B: Postoperative contrast-enhanced T1-weighted MR image obtained after a NICO Myriad–assisted endoscopic approach demonstrating near-total resection of the macroadenoma. C–E: Intraoperative images showing (in time-lapse fashion) the use of the device to remove tumor (arrow) off the right lateral aspect of the diaphragma sellae (arrowhead). F and G: Removal of the right lateral sellar tumor component demonstrating the varied trajectory and angles achieved with the device. mor (Fig. 3C–F). The solid component and cystic walls the foramen of Monro, and the handpiece aperture can be required extensive dissection. The Myriad allowed us to directed away from the fornix or adjacent veins while in quickly debulk the tumor and facilitated capsular dissec- use. Here we present a case of a 31-year-old woman who tion. There were no complications, and a complete resec- presented with a 1-week history of nausea and vomiting tion of the craniopharyngioma was achieved (Fig. 3B). and was found to have papilledema on physical examina- Colloid Cyst. Colloid cysts can be resected through tion (Case 6). An MR imaging study demonstrated a large an open or an endoscopic procedure. Many find a purely mass in the superior aspect of the third ventricle (Fig. endoscopic approach to be effective in resection, such 4A). We approached the mass with the endoscope from a that it is often the procedure of choice.15 Nevertheless, left frontal bur hole and initially punctured the cyst (Fig. colloid cysts vary in size and consistency, and the cyst 4C and D), which allowed us to completely remove the contents and walls are often thick and can be difficult cyst contents with the Myriad (Fig. 4H and I). The suc- to resect using a working-channel endoscope. We have tion and cutting aspect of the device allowed us to quickly used the Myriad in purely endoscopic resection of colloid resect parts of the cyst wall (Fig. 4E–G), and we achieved cysts. After initial puncture and opening of the cyst, we a complete resection of the colloid cyst (Fig. 4B and J). were able to efficiently remove the often thick or semi- Hydrocephalus solid cyst contents with the suction and cutting aspects of the device. After central debulking, one can then quickly The endoscope is used in many cases of obstructive remove large parts of the cyst wall to facilitate complete hydrocephalus because a third ventriculostomy can be ef- excision. This technique can prevent damage to the for- fective in 70%–80% of these cases.34,42 However, cases of nix, as large parts of the lesion are not drawn through loculated hydrocephalus are more complex and challeng-

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Fig. 3. Case 5. Craniopharyngioma. A: Preoperative sagittal and coronal contrast-enhanced T1-weighted MR images demonstrating a large enhancing sellar and suprasellar cystic and solid mass with extension into the interpeduncular cistern and mass effect on the midbrain. B: Postoperative sagittal and coronal contrast-enhanced T1-weighted MR images obtained after a purely endoscopic approach, showing complete resection of the craniopharyngioma. C–F: Intraoperative images. A large cystic and solid mass was noted upon opening the sella (C). Myriad-assisted endoscopic resection in and around the optic chi- asm (D) provided a complete resection. The Myriad device is shown in open (arrow in E) and cutting modes (arrow in F) removing pieces of the craniopharyngioma. ing.11 Enlarging loculated components of the ventricular 5C). This is illustrated in the case of a 32-year-old woman system along with trapped ventricles require fenestration who presented with bilateral shunt infection/malfunction to establish communication between these areas and other and a history of loculated hydrocephalus and a supratento- compartments within the ventricular system that are able rial primitive neuroectodermal tumor in childhood (Case to absorb CSF, or to use a single ventriculoperitoneal shunt 10). After removal of the shunt systems and antibiotic treat- catheter.11,39 These loculated walls are often thick due to ment, we used the endoscope to explore the extensive ad- previous infection or hemorrhage (Fig. 5A), and creating hesions within the right and left ventricular systems. The an adequate fenestration can require a significant amount Myriad enabled us to efficiently create a communication of time. The Myriad can be used to quickly and cleanly between the ventricular systems with large smooth-edged enlarge a fenestration (Fig. 5B). Unlike the usual blunt fen- fenestrations, allowing us to place a unilateral ventricu- estration techniques, the device’s cutting action produces a loatrial shunt instead of the previous bilateral system. Ad- smooth edge to the walls of the created fenestration (Fig. ditional case studies with longer-term follow-up are needed

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Fig. 4. Case 6. Colloid cyst. A: Preoperative coronal and axial contrast-enhanced T1-weighted MR images demonstrating a large enhancing mass in the superior aspect of the third ventricle bulging into the left Monro foramen and left lateral ventricle. B: Postoperative contrast-enhanced T1-weighted MR images obtained after a purely endoscopic approach demonstrating complete resection of the colloid cyst. C: View through the endoscope of the colloid cyst after initial puncture, showing the fornix (f), choroid plexus (cp), cyst wall (cw), and cyst contents (cc). D: Forceps closing on a piece of the cyst wall demonstrating its thick and fibrotic nature. E–G: A time-lapse sequence of intraoperative images demonstrating the precise suction and cutting action of the Myriad. The device is open in (E) and suctioning and cutting a small piece of the cyst wall (F) for removal (G). H and I: Intraoperative images showing suction and removal of the cyst contents. J: Complete resection of the colloid cyst. to determine if such techniques lead to lower reloculation Discussion or cyst recurrence rates. The technological advancements made inside the field Intraventricular Hematoma of neurosurgery are due in large part to advancements Neuroendoscopic evacuation of intraventricular he- made outside the field of medicine. The introduction of the surgical microscope27,40 and use of smaller dissecting matomas has been found to shorten the duration of exter- 41 nal ventricular drainage.26,36 The intraventricular hema- instruments specifically designed for manipulating tissue toma is often quite thick, making evacuation with suction around delicate and eloquent brain structures helped make possible what we now know as modern microneurosur- difficult. The Myriad is able to suction and shave pieces gery. 40 For example, laser technology32 was first introduced of the clot, enabling a faster removal of the hematoma to the field of neurosurgery in the 1960s for treatment of from within the ventricular system. This is demonstrat- intracerebral neoplasms. This technology has evolved into ed in the case of a 31-year-old woman who underwent a use as a laser scalpel for fenestration of arachnoid cysts, purely endoscopic resection of a colloid cyst (Case 2). Af- cerebrovascular bypass, and dural reconstruction along ter the Myriad-assisted complete resection of the cyst, an with treatment of intracerebral and intraspinal tumors.19 acute clot formed. We used the Myriad to resect the clot The use of the ultrasonic aspirator in neurosurgery was in the lateral and third ventricles (Fig. 6A and B) and cre- first reported in 1978 for the removal of intraaxial and ex- ate a septostomy. Both foramina of Monro were inspected traaxial tumors and is now a mainstay in intracranial tu- and found to be patent. mor resection.3,18 Just as the previous technologies relied

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Fig. 5. Case 10. Loculated hydrocephalus. A: An initial puncture to a ventricular wall created a small fenestration (arrow), which required enlargement with a dilating device. B: We were quickly able to remove the frayed pieces (arrow) of the punctured ventricular wall with the Myriad. C: The suction and sharp cutting aspects of the device allows the fenestration to be quickly and cleanly enlarged, creating a smooth communication (arrow) and preventing possible future scar formation. on advancements outside of medicine, better imaging,2,33 to be of most benefit in resection of thicker tissue that fiber optics, and lens development led to the emergence and otherwise would be time consuming or impossible to re- widespread use of the endoscope in neurosurgical proce- move with simple suction and dissectors. Its other addi- dures.31,43 tional benefits rely on its multifunctional capacity making Applications of intracranial neuroendoscopy contin- neuroendoscopic procedures more efficient by combining ue to expand as technology improves.5,6 Colloid cysts are actions of multiple single-function instruments. becoming more commonly treated through purely endo- Although the Myriad is the first mechanical device scopic techniques.15 The anterior skull base is becoming invented for use through the working channel, other instru- more commonly approached inferiorly through an endo- ments have been designed for tissue removal through the scopic endonasal approach.8,10,23,24 The extended trans working channel, including an ultrasonic aspirator,38 de- sphenoidal approach is gaining popularity for large pitu- veloped and designed specifically for the universal GAAB itary adenomas10 and craniopharyngiomas8 invading the neuroendoscopic system (Karl Storz GmbH & Co.). Oertel suprasellar space. Improved techniques for reconstruct- et al.38 used this device in 2 patients with pituitary adeno- ing the skull base16,25,37 after an endoscopic procedure are mas, 2 patients with obstructive hydrocephalus from intra- making these endonasal procedures more frequent. This ventricular clot blocking the aqueduct, and 1 patient with has sparked both the need for and the creation of devices obstructive hydrocephalus caused by blocking of the aque- for tumor and tissue resection using these minimally in- duct by a cystic craniopharyngioma. It was effective in all vasive approaches. patients without complications. Another instrument used The working channel of the rod-lens endoscope pro- for tissue removal includes a variable-aspiration tissue re- vides a single avenue for a variety of tools in neuroendo- section device, which was used in 2 patients with third ven- scopic procedures. Instruments, each serving a specific tricular hamartomas.30 purpose, have been invented to grab, suction, coagulate, Other Potential Uses of the Myriad System cut, or dissect tissue. We report on a device that combines many of those functions into one handpiece that works As endoscopic techniques become more widespread, through the working channel of two commonly used rigid the trend of minimalism in neurosurgery for less brain re- neuroendoscopic systems (Aesculap Co. and Karl Storz traction and therefore less damage to eloquent brain struc- GmbH & Co.). The Myriad is a novel device that appears tures will lead to an even greater use of the endoscope in intracranial lesion resection. The ability to precisely and efficiently remove these lesions depends on the technology developed. Intraventricular tumors and cysts are ideal lesions for the application of neuroendoscopy and resection with assistance of the Myriad system. Other intracranial tumors such as acoustic neuromas may benefit from its precise control. Similar to loculated hydrocephalus, arachnoid cysts throughout the brain or ventricular system are amenable to fenestration enlargement with the Myriad. Elimination of the typically frayed edges of cyst wall fenestrations may prevent future scar development and facilitate a better outcome. It appears that the uses for this device are multiple within intracranial surgery. Fig. 6. Case 2. Intraventricular hematoma. A: After a purely endoscopic resection of a colloid cyst, an acute clot formed and the Myriad This capacity for use across disciplines and procedures is was used for clot evacuation. B: With precise control of suction and important when health care purchasing budgets are lim- the oscillatory cutting action of the device, we were able to quickly suc- ited. As a result, it is likely that the Myriad will become tion and remove pieces of the hematoma until it was entirely evacuated. a mainstay and reliable companion in neuroendoscopy.

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Summary of Advantages and Disadvantages the sellar region: technical evolution of the methodology and refinement of a dedicated instrumentation. J Neurosurg Sci In the 15 cases in which we used the Myriad system 43:85–92, 1999 (Table 1), we experienced or observed the following advan- 2. Apuzzo ML, Heifetz MD, Weiss MH, Kurze T: Neurosurgi- tages: precise resection control (controlled tissue resection cal endoscopy using the side-viewing telescope. J Neurosurg with the ability to observe tissue prior to cutting and re- 46:398–400, 1977 moval through variable-strength suction); the combination 3. Brock M, Ingwersen I, Roggendorf W: Ultrasonic aspiration of multiple tools in one handpiece (scissors, suction, blunt in neurosurgery. Neurosurg Rev 7:173–177, 1984 dissection), making tissue resection more efficient than ex- 4. Cappabianca P, Alfieri A, Thermes S, Buonamassa S, de Di- vitiis E: Instruments for endoscopic endonasal transsphenoi- isting endoscopic instrumentation; rapid control of suction dal surgery. Neurosurgery 45:392–396, 1999 strength with capability of immediate cessation of suction, 5. Cappabianca P, Cavallo LM, Esposito I, Barakat M, Esposito which enhances safety during intraventricular procedures F: Bone removal with a new ultrasonic bone curette during and around critical structures; notably improved resection endoscopic endonasal approach to the sellar-suprasellar area: speed compared with other purely endoscopic instruments; technical note. Neurosurgery 66 (3 Suppl Operative):E118, lack of heat generation; low-profile handpiece, which aids 2010 visualization (Fig. 1D); compatibility with working-chan- 6. Cappabianca P, Decq P, Schroeder HW: Future of endoscopy nel endoscopes (Fig. 1D); collection of aspirated tissue in neurosurgery. Surg Neurol 67:496–498, 2007 7. Cavallo LM, Prevedello D, Esposito F, Laws ER Jr, Dusick (Fig. 1B) with minimal crush artifact (an advantage for JR, Messina A, et al: The role of the endoscope in the trans- tumor tissue analysis); malleability of tip (up to 30°); and sphenoidal management of cystic lesions of the sellar region. compatibility with both open and endoscopic intracranial Neurosurg Rev 31:55–64, 2008 procedures. 8. Cavallo LM, Prevedello DM, Solari D, Gardner PA, Esposi- Disadvantages of the Myriad include the presence to F, Snyderman CH, et al: Extended endoscopic endonasal of an additional console and equipment in the operating transsphenoidal approach for residual or recurrent craniopha- room, the learning curve associated with the device (as ryngiomas. Clinical article. J Neurosurg 111:578–589, 2009 with any new device), the lack of hemostatic or cautery 9. Couldwell WT, Weiss MH, Rabb C, Liu JK, Apfelbaum RI, Fukushima T: Variations on the standard transsphenoidal ap- capabilities, and the cost associated with the single-use proach to the sellar region, with emphasis on the extended disposable handpiece. In addition, removing extremely approaches and parasellar approaches: surgical experience in fibrous, tenacious tumor tissue is more difficult with the 105 cases. Neurosurgery 55:539–550, 2004 existing Myriad handpiece sizes than with ultrasonic as- 10. Di Maio S, Cavallo LM, Esposito F, Stagno V, Corriero OV, pirators used in open procedures. Cappabianca P: Extended endoscopic endonasal approach for selected pituitary adenomas: early experience. Clinical article. J Neurosurg 114:345–353, 2011 Conclusions 11. El-Ghandour NM: Endoscopic cyst fenestration in the treat- The Myriad is a minimally invasive surgical system ment of multiloculated hydrocephalus in children. J Neuro- surg Pediatr 1:217–222, 2008 specifically designed for the removal of intracranial and 12. Elliott RE, Hsieh K, Hochm T, Belitskaya-Levy I, Wisoff J, skull-base soft tissues with direct, microscopic, or en- Wisoff JH: Efficacy and safety of radical resection of primary doscopic visualization. It is precise in tissue cutting and and recurrent craniopharyngiomas in 86 children. Clinical ar- removal without the use of heat or ultrasonic energy. It ticle. J Neurosurg Pediatr 5:30–48, 2010 is surgeon controlled for real-time variable aspiration for 13. Elliott RE, Wisoff JH: Successful surgical treatment of cra- fine-tissue removal. It is effective in efficiently removing niopharyngioma in very young children. Clinical article. J fibrous pituitary tumors, craniopharyngiomas, and col- Neurosurg Pediatr 3:397–406, 2009 loid cysts that otherwise would be technically difficult 14. Gardner PA, Kassam AB, Snyderman CH, Carrau RL, Mintz AH, Grahovac S, et al: Outcomes following endoscopic, ex- with standard endoscopic instrumentation, given the con- panded endonasal resection of suprasellar craniopharyngio- sistency of these lesions. It is also effective in enlarging mas: a case series. J Neurosurg 109:6–16, 2008 fenestrations for loculated hydrocephalus and removal of 15. Greenlee JD, Teo C, Ghahreman A, Kwok B: Purely endoscop- intraventricular hematomas. Further uses of this device ic resection of colloid cysts. Neurosurgery 62 (3 Suppl 1): abound and the Myriad will likely become an important 51–56, 2008 tool in the resection of intraventricular masses. 16. Hadad G, Bassagasteguy L, Carrau RL, Mataza JC, Kassam A, Snyderman CH, et al: A novel reconstructive technique Disclosure after endoscopic expanded endonasal approaches: vascular None of the authors have any financial relationships with or are pedicle nasoseptal flap. Laryngoscope 116:1882–1886, 2006 employed by the NICO Corporation. Dr. Greenlee is a member of an 17. Iuchi T, Saeki N, Tanaka M, Sunami K, Yamaura A: MRI pre- Aesculap, Inc., advisory board. diction of fibrous pituitary adenomas. Acta Neurochir (Wien) Author contributions to the study and manuscript prepara- 140:779–786, 1998 tion include the following. Conception and design: all authors. 18. Jallo GI: CUSA EXcel ultrasonic aspiration system. Neuro- Acquisition of data: all authors. Analysis and interpretation of data: surgery 48:695–697, 2001 all authors. Drafting the article: all authors. Critically revising the 19. Jallo GI, Kothbauer KF, Epstein FJ: Contact laser microsur- article: all authors. Reviewed final version of the manuscript and gery. Childs Nerv Syst 18:333–336, 2002 approved it for submission: all authors. Administrative/technical/ 20. Jane JA Jr, Kiehna E, Payne SC, Early SV, Laws ER Jr: Early material support: all authors. Study supervision: all authors. outcomes of endoscopic transsphenoidal surgery for adult craniopharyngiomas. Neurosurg Focus 28(4):E9, 2010 References 21. Jho HD, Alfieri A: Endoscopic endonasal pituitary surgery: evolution of surgical technique and equipment in 150 opera- 1. Alfieri A: Endoscopic endonasal transsphenoidal approach to tions. Minim Invasive Neurosurg 44:1–12, 2001

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22. Jho HD, Carrau RL: Endoscopic endonasal transsphenoidal doscopic third ventriculostomy in fourth ventricular outlet surgery: experience with 50 patients. J Neurosurg 87:44–51, obstruction. Neurosurgery 63:905–914, 2008 1997 35. Naganuma H, Satoh E, Nukui H: Technical considerations of 23. Kassam A, Snyderman CH, Mintz A, Gardner P, Carrau RL: transsphenoidal removal of fibrous pituitary adenomas and Expanded endonasal approach: the rostrocaudal axis. Part I. evaluation of collagen content and subtype in the adenomas. Crista galli to the sella turcica. Neurosurg Focus 19(1):E3, Neurol Med Chir (Tokyo) 42:202–213, 2002 2005 36. Nomura S, Ishihara H, Yoneda H, Shirao S, Shinoyama M, Su- 24. Kassam A, Snyderman CH, Mintz A, Gardner P, Carrau RL: zuki M: Neuroendoscopic evacuation of intraventricular hema- Expanded endonasal approach: the rostrocaudal axis. Part II. toma associated with thalamic hemorrhage to shorten the du- Posterior clinoids to the foramen magnum. Neurosurg Focus ration of external ventricular drainage. Surg Neurol Int 1:43, 19(1):E4, 2005 2010 25. Kassam AB, Thomas A, Carrau RL, Snyderman CH, Vescan 37. Nyquist GG, Anand VK, Singh A, Schwartz TH: Janus flap: A, Prevedello D, et al: Endoscopic reconstruction of the cra- bilateral nasoseptal flaps for anterior skull base reconstruc- nial base using a pedicled nasoseptal flap. Neurosurgery 63 tion. Otolaryngol Head Neck Surg 142:327–331, 2010 (1 Suppl 1):ONS44–ONS53, 2008 38. Oertel J, Krauss JK, Gaab MR: Ultrasonic aspiration in neu- 26. Komatsu F, Komatsu M, Wakuta N, Oshiro S, Tsugu H, Iwaasa roendoscopy: first results with a new tool. Technical note. J M, et al: Comparison of clinical outcomes of intraventricular Neurosurg 109:908–911, 2008 hematoma between neuroendoscopic removal and extraven- 39. Oertel JM, Schroeder HW, Gaab MR: Endoscopic stomy of tricular drainage. Neurol Med Chir (Tokyo) 50:972–976, the septum pellucidum: indications, technique, and results. 2010 Neurosurgery 64:482–493, 2009 27. Kurze T: Microtechniques in neurological surgery. Clin Neu- 40. Rand RW, Jannetta PJ: Microneurosurgery: application of rosurg 11:128–137, 1964 the binocular surgical microscope in brain tumors, intracra- 28. Landolt AM, Osterwalder V: Perivascular fibrosis in prolacti- nial aneurysms, spinal cord disease, and nerve reconstruction. nomas: is it increased by bromocriptine? J Clin Endocrinol Clin Neurosurg 15:319–342, 1968 Metab 58:1179–1183, 1984 41. Rhoton AL Jr: Operative techniques and instrumentation for 29. Laws ER Jr: Transsphenoidal removal of craniopharyngioma. neurosurgery. Neurosurgery 53:907–934, 2003 Pediatr Neurosurg 21 (Suppl 1):57–63, 1994 42. Sacko O, Boetto S, Lauwers-Cances V, Dupuy M, Roux FE: En- 30. Lekovic GP, Gonzalez LF, Feiz-Erfan I, Rekate HL: Endo- doscopic third ventriculostomy: outcome analysis in 368 pro- scopic resection of hypothalamic hamartoma using a novel cedures. Clinical article. J Neurosurg Pediatr 5:68–74, 2010 variable aspiration tissue resector. Neurosurgery 58 (1 Suppl 43. Siomin V, Constantini S: Basic principles and equipment in 1):ONS166–ONS169, 2006 neuroendoscopy. Neurosurg Clin N Am 15:19–31, 2004 31. Li KW, Nelson C, Suk I, Jallo GI: Neuroendoscopy: past, present, and future. Neurosurg Focus 19(6):E1, 2005 32. Lin LM, Sciubba DM, Jallo GI: Neurosurgical applications of Manuscript submitted December 14, 2010. laser technology. Surg Technol Int 18:63–68, 2009 Accepted February 11, 2011. 33. Liu CY, Wang MY, Apuzzo ML: The physics of image forma- Address correspondence to: Jeremy D. W. Greenlee, M.D., tion in the neuroendoscope. Childs Nerv Syst 20:777–782, Department of Neurosurgery, University of Iowa Hospitals and 2004 Clinics, 200 Hawkins Drive, Iowa City, Iowa 52242. email: jeremy- 34. Mohanty A, Biswas A, Satish S, Vollmer DG: Efficacy of en- [email protected].

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